


bad moons call

by alluran



Category: Voltron: Legendary Defender
Genre: Asexual Character, Demisexuality, F/M, mermaid au, shallura - Freeform, siren au
Language: English
Status: In-Progress
Published: 2016-10-13
Updated: 2016-10-14
Packaged: 2018-08-22 03:38:29
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,852
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8271226
Author URL: https://archiveofourown.org/users/alluran/pseuds/alluran
Summary: The first time he sees it out there, it’s just a bolt through the churning waters - ghosting through the low fog and stealing light from the waxing moon. It’s easy to convince himself he’s dreaming, that it’s just so late on lookout and the old legends of Calypso told over dinner get to his head, so he does. It’s his first voyage across the great seas and whatever he sees moves too fast for him to be sure of what it is - most likely a group of fish migrating to the warmer waters or even the crew fooling him to call out and fall into some grand trick or another.A splash and a terrified shout from the bow jerks him out of his reverie. “Siren!”





	1. Chapter 1

**Author's Note:**

> prompt: siren and asexual pirate who doesn’t understand why all his crew are losing their shit that person has a nice voice sure but what the fuck is happening.

_they send me away to find them a fortune, a chest filled with diamonds and gold_ _  
the house was awake with shadows and monsters_

* * *

The first time he sees it out there, it’s just a bolt through the churning waters - ghosting through the low fog and stealing light from the waxing moon. It’s easy to convince himself he’s dreaming, that it’s just so late on lookout and the old legends of Calypso told over dinner get to his head, so he does. It’s his first voyage across the great seas and whatever he sees moves too fast for him to be sure of what it is - most likely a group of fish migrating to the warmer waters or even the crew fooling him to call out and fall into some grand trick or another.

A splash and a terrified shout from the bow jerks him out of his reverie. “ _Siren!”_

A gust of wind howls through the shrouds and more voices rise up. He leaves his station at the stern and sees the silhouette of someone shooting blindly into the water. Her existence is cursed and seethed and spat on as half of the crew stomps back up to the deck from the cabins. They lean over the sides to catch a glimpse of the nightmarish creature and clumsily gather towards the center. He realizes that he should be shaken and alert whenever _she_ appears.

But he’s never been one for superstition.

Two nights later, a song finally rings out over the waves and dulls the _whoosh_ of wind in their ears and stills their ship completely like they’re being hovered just over the water. Suspended by her warm, swinging alto and stopping time altogether, lighting the stars like diamonds against the dark, deep sky. And as the song shifts, pitching into a dangerous soprano that has even the most hardened of their crew shivering at their posts, Shiro relents and accepts - superstition may not be completely as impractical as he once believed.

* * *

There’s talk of turning back or changing their direction altogether. The captain sits at the head of their long table, surrounding himself with yellowing maps in three languages and heavy tomes with crudely drawn figures of menacing beasts that were believed to be at the siren’s whim and call. As the candles dim, their shadows grow taller - inching up and up and up to the ceiling in menacing shapes and an ominous air chokes the room as they talk of the songs.

He doesn’t mention that the song isn’t haunting to him.

That it doesn’t call him to climb over the side and ludicrously dive to his end in a fervent search of lithe arms and curving hips under the rough skin of his palms. No, it stills him, rooting him firmly in place and bleeding a calm through his veins as his mind sinks back to the familiar roads of home and the sun shining down on him. So he believes - _knows_ \- her kind _are_ out there, breaking the haunting silence of night, but doesn’t fear.

A hand full of his shipmates notice his lack of fright and torn nerves and his heartbeat labors as they look over him. The second mate scowls, “One less person to tie to the canons when they return at night, back to work.”

For that, he catches lookout duty more and more as the songs become more frequent and grow louder and more intricate. There’s a woven harmony just at the reaches of the horizon that leeches like a plague on their journey, crew members’ hands dot with the crescent moons of their fingernails as they war with their senses. The songs start as the last ray of sun is swallowed by a wave and won’t end until at dawn - as the lingering days of summer trickle into the colder months, the nights stretch longer; chasing most of the crew below decks to the stifling press of their bunks.

Shiro plays his part, swallowing thickly and pressing his mouth into a thin line when he’s assigned to lookout. Nods resolutely as his captain claps his shoulder mournfully and reminds him of their mission. Says that he hopes Shiro will be there to greet the shores of home with them, his encouraging speech falters and silently drops off as the older man pales when he meet Shiro’s eye.

As if he speaks to a man already dead.

Maybe he is. Perhaps death has chosen its next mark, but it won’t be because he’s fighting to feel the soft skin of a faceless creature at the bottom of the ocean.

* * *

That night she breaks the surface of the water and watches him closely.

She isn’t scowling or smiling and a part of him feels relief that mouth doesn’t yawn open to sing, flashing serrated teeth in the low light of the moon. He comes to his decision as he breaks their gaze to slowly bow his head.

When he raises his eyes back to hers, he takes her silence in and accepts it as a sign that - for now - he is in the clear and has her attention. “The first night I saw you, I was afraid you were a survivor of a shipwreck. I nearly tossed a rope out to you and called for help. Then, I thought it was perhaps the crew getting a laugh on their new shipmate.” He huffs bemusedly to himself when she watches him unblinkingly, her eyes only leaving his to trail down to his waist where his captain’s revolver and his own sword sat at his hip. “You don’t know what I’m saying do you?” Shiro ducks and bashfully scrubs his hand over the back of his head. “Of course sirens wouldn’t speak English and I’m venturing to guess you wouldn’t bother to learn for us mangy things.”

Her brows lower, an emotion he can’t name flaring in her eyes. “We know _all_ languages.” The water laps away from her shoulder as she raises higher and he startles, looking away as the tips of his ears grow warm. This time, she laughs. “You worry I’m not decent.”

Something restless turns over inside him at her words, they aren’t an order, not a command that takes him wholly - body, mind, and soul - but a _challenge_. He wonders at the accent of her voice and the way it dips teasingly over her voice and it’s familiar as if they were once introduced and long acquaintances growing comfortable with each other. A dull hook tugs at his ribcage.

Shiro thinks perhaps maybe he _should have_ heeded the warning of his captain because he looks back to her with peaked curiosity. A silver chest plate starts at the base of her neck, covering her shoulders and collarbones, and drops low to cover her torso. Small patches of skin show through the sporadically scaled v of her hips before the dark blue scales of her tail begin. The armor is tarnished in places with tiny dents in others, but still shines brightly in the moonlight. Bare and strong arms hang at her sides and a word rings crisp in his ears.

_Warrior._

He bites his tongue against a thousand and one questions and tips his head back in the direction of the bow. “You’ve got the crew in quite a fever.”

She scoffs, rolling her eyes. “We are not interested in a cargo ship, we call for a greater enemy.”

The siren breathes heavily and fear catches in his throat - there’s not much that can shake him up, but the bite to her words has his spine straightening with dread. “You’re hunting.”

“In not so many words, I suppose that’s correct.” She juts her chin up, her eyes narrowing on him and he knows immediately he’s being measured. “You here our song, but you are not scared.”

It isn’t phrased like a question, but he steps up and curtly nods. He can only guess that she’s satisfied with his answer when her hand raises from the water, reaching towards him. He wavers - it could be that he’s no different and this is how he’s to discover it.

“I am Allura, princess of the Alteans.” The webbing between her fingers falls back like drops of water rolling back over her wrist to reveal long, dark fingers and he takes it.

“Shiro, lowly crew member of the unimpressive cargo ship.”

Her eyes flash and distinctive markings that follow the curve of her eyes glow as the corner of her mouth ticks up. His hand wraps around hers and her fingers tenses around his. “Then be warned, you and the rest of your crew, you must leave, Shiro. The Galra are in these waters, they are what we hunt.”

His hand shakes in hers and he feels like he’s been knocked over into the cold waters, his breath stolen and senses blank. “ _They’re_ here?!”  

 _“Yes._ ” Her hand snakes up to his wrist and pins him in place with her hard stare.

“Are we headed into their territory? Are they sailing in a fle-”

**_“Shiro?!”_ **

He curses under his breath, just barely catches the own she hisses, and drops her hand. Shiro jerks back several steps and spins around on his heel. Footsteps fall closer and closer to him. He whispers back over his shoulder,“You’d better go, and th-”

His words die on his tongue as he catches the inky shade of her fins quietly flick over the surface and disappear.

* * *

([prompt source](http://nerds-are-cool.tumblr.com/post/133544218971/if-youre-struggling-for-au-ideas-take))


	2. Chapter 2

_others sail on the sea  
with the keys to the cage   
and the devil to pay_

* * *

 

The wind dies in their sails. The sun can’t break through the clouds that churn sickly above them and hope floats away like a dying ember.

Shiro chases sleep fruitlessly and his stomach rolls with the bobbing of the ship as her warning goes unheeded - there’s no way he can sanely justify _knowing_ the Galra are around, let alone how he comes across such a dire piece of information. Even if superstition comes in oceans worth. If he admits to speaking with her, trusting her, and even _touching_ her, they’ll move him to the cells quicker than he can blink. There would be no way to convince the crew that she didn’t tether him with her song. 

The captain relieves him from lookout the next three nights - they can’t take any chances and he’s not about to let some slimy siren lull him into a false sense of comfort because his navigator hasn’t yet tried to tie weights to his boot straps.

But the sour turn of the weather plays in his favor, superstitions run higher and higher and higher while dread coils low in their middles. The songs come back, the notes high and shrill - sharp and fast - and it doesn’t take much to convince his captain and first mate to let him take that evening’s shift. There’s a plan half-forming in his head and a crick in his neck from the way he’s standing when she makes her return.

One moment there’s nothing but the eerie night yawning before him and the next, serrated teeth flashing and electric shades of blue jarring his head - pointed nails catching in his tunic and yanking him forward -  and he startles, _hard_. Shiro recognizes fear on his tongue, but it mixes with something else he can’t name that has adrenaline crashing through him and his pulse hammering against his temple. It’s all he can do to blink and remember to breathe as she seethes in his face, eyes dimming in the moonlight.

He shoves a hand up, raking back the wild tuft of hair that hangs in his face like grimy seaweed. He heaves a great breath and lurches in her hold.

“ _That’s_ what’s supposed to make men fall into the ocean for you?” He mutters curses under his breath trying to shake the weighted feeling off his limbs, but doesn’t miss the angry line of her mouth break as one side twists up. She lets go of his shirt and his palms slap against the slick edge of the deck. Shiro sucks in a surprised yelp as he tilts over the side and sees nothing but unsettled waters swirling and raising, encompassing her tail and holding her up. His eyes cross and he shoves himself back, stumbling until he’s falling back, landing hard on the deck.

“No, _that’s_ what the unimpressive cargo ship’s _navigator_ gets for not listening and _navigating_ out of the way of a war older than their time.”

“Wait, navi-” He freezes, dumbly blinking at her. “You’ve been listening.”

“I have.” Her voice borders a purr and her smile turns Cheshire as she skims her hands over the water at her waist.

Anyone else may have been wise enough to be wary or bothered, but he can’t find it in him. Instead, it’s a comfort. His nights were spent worrying for her, worrying for the ship, because if she left and the Galra came, they were done for or the Galra _defeated_ her, then she….”Then, you know-”

“That you call me in your dreams.”

He blinks - once, twice, three times and then, a fourth because he’s exceptionally eloquent tonight. “I-it’s not- I-”

“I know.” She hums and his chest warms, his heart buzzing safe beneath his bones. 

The stress and sleepless nights slink over the thrum of her voice and sink further from the forefront of his mind. He thinks about the shores of home, the sand warm under his feet and laughter rising up into the clouds - mixing with the excited caws of the seagulls. Clean sheets tuck under his chin, the summer breeze inviting its way in through the opened window. 

It’s only when Allura speaks, _“Sorry,”_ , clearing her throat, that he’s snapped back to the overwhelming hollow of being human and he understands her apology and the flush rising fast over her nose and cheeks. Her eyes flick from the center of his chest back up to his eyes.

“I wasn’t- there are different kinds of song a-and only those who _want_ to hear can.” Her hand stretches forward, taking a firm hold around his once more. 

He’s fighting his own blush - by the heat edging his collar, he guesses he’s doing a good as job as she is. “The wind’s moved out, Allura. We-we’re stranded. They know, they watch the clouds and respect the sea with all of their salt, bu-”

 _“Haggar.”_ Allura spits the word like venom from her mouth, gritting her teeth as she looks into the shrouds. The dulled tips of her nails flex into his skin, retracting immediately. The siren looks back to him, becoming more irritated when he can only give her a shrug, he doesn’t recognize the name. “She is the sea witch from far waters that Zarkon has kept close in recent times, growing and feeding his hunger for war and death, wealth and power. She’s the reason why the wind moves out. They must know you are out here with her eye.”

“Her _what_?” 

Her hands jump to his shoulders and squeeze. “The Galra _will_ take the ship and raise their own flags. _Takeshi_ , they do _not_ take prisoners.”

Shiro furrows his brow, “And you?”

“You worry for a siren warrior?” She scoffs, waving off his serious demeanor. “You certainly are an _odd_ creature.”

“You’ve gone out of your way not to sink me and, last I checked,” he gestures widely behind him, “Other than being mildly uncomfortable and scared out of their wits, none of the crew have turned up missing. Humans and siren are alike, we don’t all share the same purpose.”

She studies him for a few minutes, and, for once, he’s not nervous under her steady gaze. Allura begins hesitantly, “I wish to give you something, but I only want to do so with your permission.”

“If you’re going to sing again, I’d rather pass up the encore.” He laughs and raises is hands up, stepping back.

Her eyebrows climb high on her forehead and he thinks maybe he’s stumbling over the threshold of her patience and manner. “Oh, you fancy yourself devilishly humorous, don’t you?”

The corner of his mouth ticks up at the playful light in her eyes. “What could a siren possibly want to impart on me?”

“Her favor.” Allura’s hand takes his once more, but slides around his wrist and up to the crook of his elbow, guiding his own hand to hers. The ocean water ghostly cold compared to the warmth of her dark skin. “You have my word, Takeshi.”

Shiro takes a shuttering breath as he steps closer, his vision tunneling so it’s only the starlight gleam of her hair, pearly glow of the markings high on her cheeks, and the softened welcome in her eyes. “I trust you.”

Allura raises, high enough to meet his eye, and leans to him over the deck.  “No matter where the sea or stars take you, Navigator, I shall hear your call.”

Her word crackles to life within him when her mouth falls on his cheek, trailing to his fingertips and down his spine.

**Notes for the Chapter:**

> yep, this is an ongoing story! It is one that centers around Shiro and Allura, which is why they're the only ones tagged. each part of this story is posted to my tumblr first (alluran.tumblr.com) and then, added to ao3 when I get the time.
> 
> more importantly: demi siren allura


End file.
